Screw-propeller.



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SCREW IBQPELLEB. APYLIUAIIMT lIL-D JUNE 30, 1911.

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SCREW PBOPBLLEB. l

, 11. 1,015,540. Patented Jan 23,1912.

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A of the Empire of Germany,

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Specification of Letters Patent. Applcationled June 30, 1911.' Serial N0.'636,212.

To all whom 'it may concern:

Be it known that I, CARL BTOW, a citizen residing at Nuremberg, in the Empire of ofnwhich the following is a specification.

My inventionconsists of improvements in screw-propellers, whereby .the driving eapa'city of the propeller is considerably in 10 creased. f

One improvement consists in that each lblade of the `propeller partially Compasses the nave. Thereby the connection between -blade andnave is greatly strengthened.

Another improvementconsists in that thetwo furcate portions of each blade near the nave are helically wound and conically disposed on the nave, so that two cone-like members are formed at the ends of the nave.

The new screw-propeller may be employed in connection with a ventilator or for'driving water-ships or dirigible balloons, aero- 1 planes and the like.

:I will now proceed to describe my inven- '25 tion with reference to the accompanying drawings, in whiohv Figure 1 is a rear end elevation of a screwpropeller designed for ships, Fig. 2 is a top plan View of the same, Fig. 3.is a side view of one blade of the propeller spread in a plane or prior to being fitted to the nave, Fig. 5 is a plan view of a slightly modified form of screw-propeller, Fig. 6 illustrates ht angles to Fig/5, Fig. 7 is an end elevation view of the same, v an Fig. 8 shows the active surface of one blade Aof a screw-propeller for aeroplanes andthe like spread in a plane similarto Germany, have" 5' invented a -new and useful Screw-Propeller,

lcessive radial line vof the nave.

.lying in the the active surface or end portion 3 of either blade ,2 forms' a `sort oflcone upon the nave, the two cones taperinlg inward. After the blade 2 is blanked out "and before its surface is curved, it presents a plane ligure like or similar to that which is shown in'Fig. 1,.being substantially oval in contour and having one end bifurcated, the inner edge .3.ofthe furcate portion or winding member, having a substantially oval curvature. Thesein'ner edges, when fitted, to the nave, lon a helical line, are inclined to the axis of said nave in such rela-y tion that the inclination varies at each sucy When improved screw-propellerrotates it produces, with its front 4 cone, whereby the water. near inward and on leaving the cone it is forced under the active plane surface 2 and on entering the rear y cone the water will be pushed outward.

- The modified forni of' screw-propeller, illustrated in Figs. 5 to 7 inclusive is similar to the one described, and differs therefrom in that each blade 5 is not plane. Its peripheral outer portionfrom z' through j to c in Fig. 7,' forms a winding vsurface as in ordinary vscrew-propelle'rs the points i and k maximum width of the blade 5. The generatrix of this winding surface is `assumed to be approximately at-right angles 4. From the points f to the axis of the nave z' and 7c to the ends Z and m respectively of the winding end portions, 6 the generatrix is, on the contrary, more inclined outward to theaxis of the nave 4, so that a sort of cone is formed at each end of the nave 4, as is best seen from,l

Fig. 5.

. -In Fig. 5,'the modiiied form of screw- Patented J an. 23, `1912.

a sucking eiiect,` the nave is drawn gradually more and 40 Fig. 4.

imilar characters of reference designate v 'similar parts throughout the several views. The propeller comprises a cylindrical nave 1 and two lades 2, 2, which, as in Fig. '1, are 5, 5. In both forms t 45 elliptic or oval and each blade partly ensubstantiallyelliptic in shape in the` end 1.00 compasses the nave 1'.v The inclined blades 'views (Fgs. 1 and7), The form shown in 2, 2 are practicall plane from the outer end Figs '5, to 7 also differ from the first dee to the central p ane ofthe navel ,passing scribed propeller, shown at Figs. 1 to 3, in through the line a--b in Fi 1. From the Ithat the ends of thefwinding endlportions 50 central plane indicated'by t e line a-rb. the

p 6,16, of the `respective*blades terminate at innerbifurcated end portions of each blade diametrically o posed'points, onthe nave, as wir 2 areconically wound, as is indicated by the i).-

Y c shown 'in I* ig. I desire it' to be expressly radial lines'in'Fig. 1 and by the shading in understood, however, that l'. do not limit my- 2 and 3. self toany angle, betweenwhlch each wind- Fi. i y 55 K best seen from Fig.- 2,- each furcatibn l. ing end portionof any blade lies.v The nave, 110

propeller (Fig. 2) and the two cones differs from .the `preceding one in that the nave 4 1s made longer roject from the blades e two blades are madethe like the blades well employed in l which hitherto has been ,assumed to be perfectly cylindrical, may have any proper shape, as in ordinary screW-propellers.

For aeroplanes, navigable balloons and of the improved screwpropeller will require to be made longer, as for example, shown at Fig. 8, Where a plane blade with its Winding end portions spread in a plane is drawn. Of course also for aeroplanes and the like the blades of the improved screw-propeller may be shaped in any proper manner, the essential point being, that the Winding end portions of the blade be conically Wound around the nave as described. A

For motors of aeroplanes and the like coupled Wit-l1 screW-propellers this improved screw-propeller presents the advantage, that the current of `air expelled from the rear 'one will effectively cool the motor.

The new screw-propeller may be equally toysv 'and models.

claim: v 1. A propeller-blade comprising a sheet of flat material having its lesser end bifurcated, t each furoation of` said sheet being gradually tapered to a point, and inclosing an aperture of substantially oval shape, the said furcations being adapted to be secured to the nave of a propeller in such relation that while the greater portionof the sheet of material s tands perpendicularly to the axis of the nave the pointed end surfaces of the :turcations are on planes parallel to said axis.

`cured to the nave 2.A A propeller, each-blade of which when spread upon a -plane has one end bifurcated and incloses an aperture of substantially oval shape, bothv furcations of each blade being taperedlto a point and adapted to be sein suchva manner that the plane of the vfun'zations is graduallymore and more inclined toward the nave and the points of the said furcations lie Hat on the nave.

3. A propeller with two'. or more blades, each blade of which when spread upon a vplane has one end bifurcated so as to inclose an aperture of substantially oval shape, each ofthe furcations beingtapered to a such a manner that the fucatilons are more point V and adapted to Abe secured to the nave in' and` moreinclined toward the nave and the points of the said furcationslie flat on the have.

4. A propeller with .two or more blades,

each of whlch when spread upon a plane has one end bifurcated of substantially oval shape, each furcation of each blade being tapered to av point and adapted to be secured to the nave in such a manner that the generatrix in the middle of each-blade and the of the same blades are at right angles one to another.

i CARL BUTOVV. Witnesses: I

WILHELM HEYDOLPH,

GG. Krrmfm.v

and incloses an aperture generatrix in both points Y 

